In earth working activities (e.g., mining, construction and dredging), ground engaging products are commonly provided on all kinds of earth working equipment (e.g., draglines, cable shovels, face shovels, hydraulic excavators, buckets, blades, rippers, dredge cutter heads, etc.) to protect the underlying equipment from undue wear and, in some cases, also perform other functions such as breaking up the ground ahead of the digging edge. Ground engaging products include, for example, buckets that mount on excavating machines, lips that attach to buckets, and teeth and shrouds that are secured to lips.
During use, ground-engaging products for earth working equipment can encounter heavy loading and highly abrasive conditions, which leads to wear or damage to the products, less remaining wear life of the products, and reduced efficiency for the earth working equipment. Moreover, a ground engaging product will occasionally encounter a material that is harder than the surrounding material being mined (e.g., a rock), subjecting the product to impact and/or higher loading that may lead to deformation, cracking, and/or a higher wear rate of the product than would otherwise be expected. The increase in the wear rate and/or damage caused to the ground engaging product may lower the total effective wear life of the product. If the products are not replaced at the appropriate time, a product may wear beyond the expected life and/or break or become unexpectedly separated, which may result in lower equipment digging efficiency, and may expose other components of the excavating equipment leading to the other components experiencing unnecessary wear.
Heavy loading and abrasive conditions can cause ground engaging products to become disengaged and separated from the earth working equipment. The operators of earth working equipment are not always able to see when a ground engaging product has become separated. A separated ground engaging product may cause damage to downstream processing equipment. For example, if a separated ground engaging product is fed into a crusher, the product may be ejected and cause a hazard to workers, or it may become jammed and cause costly crusher downtime. A jammed crusher requires shutting down the machine and having an operator dislodge the part, which at times may be a difficult, time-consuming and/or hazardous process. Additionally, continuing to operate the excavating equipment with missing ground engaging products can decrease overall productivity, and may cause the base, upon which the product was secured, to experience unnecessary wear.
There are existing systems that have been used to monitor wear parts in an effort to determine when a wear part needs replacement and/or has been lost with varying degrees of success. For example, the Tooth-Wear Monitoring system and Missing Tooth Detection system sold by Motion Metrics uses an optical camera mounted on the boom of the excavating equipment to determine the amount of wear in the wear parts and when wear parts are lost. Likewise, U.S. Pat. No. 8,411,930 discloses a system that relies on a video camera mounted to the boom of an excavating machine for detecting damaged or missing wear members.
In U.S. Pat. No. 6,870,485, a spring-loaded switch is provided between wear part components so that when the components separate, an electrical switch activates a radio transmitter alerting the operator that a wear part has been separated. In U.S. Pat. No. 5,743,031, an actuator is attached between the tooth and the nose, which, in one example, actuates a smoke canister to provide a visual signal that the tooth has fallen off.
U.S. Patent Application 2014/0311762 discloses a sensor within the mounting cavity of the wear part to measure the level of wear in the part. The sensor communicates the sensed data wirelessly to a processor for determining the level of wear. Fitting the sensor at the inner end of the cavity protects the sensor from wear and damage, and permits it to measure the wearable end of the part. Similarly, PCT Application WO 2012/0122587 discloses a system for monitoring wear in a liner or other ground engaging product by installing a sensor through the thickness of the part and connecting the remote end of the sensor to a processor for determining the level of wear. The remote end can connect to the processor via a cable or a wireless connection.